Shot shell construction



April 7, 19.64 H. A. LOCKWOOD SHOT SHELL CONSTRUCTION 2 Sheets-Shet 1 Filed April 27, 1961 INV EN TOR. Harry A ZockwamL April 7, 1964 H. A. LOCKWOOD sao'r SHELL CONSTRUCTION Filed April 27, 1961 2 Sheets-Sheet 2 W W? INVENTOR. Ha ry A .Zock Wood United States Patent 3,127,837 SHQT SEELL CONSTRUCTION Harry A. Lockwood, Westport, Conn. DriAire Inc, 26 Fitch St, East Norwalk, Conn.) Filed Apr. 27, 1961, Ser. No. 105348 6 Claims. (Cl. 10242.)

This invention relates to shot shells, and more particularly to the wad and case structures of such shells.

An object of the invention is to provide a novel and improved, force-absorbing highly axially compressible wad for shot shells and the like, which wad is controllably compnessed or reduced in its axial or front-to-back dimension in response to the explosive force of the powder charge.

In eifecting this control of the compression of the wad the invention provides a round, hollow, flexible and resilient vented box-like wad structure which is constituted ofresilient plastic substance and which has spaced front and back Walls, said wad structure having an annular side wall characterized by a deeply grooved formation which in the illustrated embodiment comprises a plurality of deep, circularly extending, annular grooves having different depths and having relatively wide mouth portions. The Wad further has a novel arrangement of bleed or vent means in its end walls, to aid in providing control of the compression.

It is found that by such hollow, resilient, annularly grooved vented wad structure the force which results from ignition of the powder charge of a shell in which the wad structure is incorporated will effect a rapid initial axial contraction of the structure which is control-led so as to reduce the peak pressure resulting from the explosion and to allow the pressure to build up relatively gradually.

Another object of the invention is to provide an improved wad construction as above set forth, which may be axially compressed to a maximum degree notwithstanding the plurality of annular grooves and venting which effects control of its axial compression.

As shown in the illustrated embodiment of the inven tion, several annular grooves are provided, and in effecting the compressibility said grooves have difiering depths whereby there is avoided an appreciable buildup or stacking of the bends or folds making up the groove formations.

A further object of the invention is to provide a wad construction as above characterized, wherein the action of the explosion effects a radial expansion of all of the side Walls thereof so as to minimize leakage and blowby at the wad and increase the efiiciency of the shell.

Still another object of the invention is to provide an improved wad construction as above characterized, wherein there is a printable surface on which data, indicia and the like may be imprinted for the information of the user, such data, imprints, etc. being readily visible through the side wall of the shell case when the latter is made of a transparent or translucent substance. In effecting this the grooved wad structure as provided by the invention is characterized by a multiplicity of grooves which are preferably disposed in sets or pairs located on opposite sides of a cylindrical, smooth-walled intermediate portion, such intermediate portion being suitable for receiving the said imprints, or for being otherwise marked with data or information.

Preferably, as illustrated herein, the said intermediate portion is made of slightly smaller diameter than the remainder of the wad so as to minimize the likelihood of the imprinted material being rubbed off or otherwise disturbed at the time that the wad is being positioned in the shell case.

Yet another object of the invention is to provide a novel and effective combination of plastic shot shell case having an integral bulbous front nose of reduced wall thickness in conjunction with a grooved, readily and highly com pressible Wad structure, thereby to obtain a useful and practicable shot pattern while at the same time ing undesired rupture of the side walls of the shell case at points appreciably behind the integral thin-walled front nose portion.

An additional object of the invention is to provide a novel and improved plastic shell case construction having an integral bulbous front wall or nose portion, wherein novel means are incorporated to restrict the fracture of the nose portion to a confined circular or annular zone extending around the base of the bulbous front wall, the improved case construction greatly minimizing fracture, cracking and the like of the cylindrical side walls of the case.

This is accomplished, in accordance with the invention, by the provision of a novel combination of external and internal annular indentions disposed adjacent each other at the base of the nose portion whereby there is effected an appreciable weakening of the walls by virtue of a reduction in thickness thereof and also by virtue of the effecting of changes in the direction of the grain structure and molecular orientation of the plastic substance.

A still further object of the invention is to provide an improved primer-supporting base member constituted entirely of plastic substance for use in a plastic shell case, said member being especially effective in frictionally retaining the primer in place while at the same time providing adequate space for the powder charge and preventing leakage or blow-by of gases between the primer base and the rear Walls of the shell case. In accomplishing this, there is provided a cup-like and plug-like structure of plastic substance having a hollow central boss and a peripheral skirt surrounding and spaced from the boss whereby the intermediate space can accommodate a portion of the powder charge. The primer is press-fitted in the'hollow boss, and to supplement the frictional retaining forces a plurality of reinforcing webs are provided, extending between the outer surfaces of the hollow boss and the base portion of the peripheral skirt. *It has been found that the action of such webs is extremely effective in increasing the frictional forces tending to retain the primer in its proper place the supporting base member.

Yet another object of the invention is to provide an improved combination plastic shell case and plastic primer base member wherein the latter is retained in its operative position by an interlocking construction pro vided on its periphery and on the back edge of the shell case.

A feature of the invention resides in the provision of an improved wad, Wad-and-case combination, and primer base structures having the above advantages and which are nevertheless simple in construction, reliable in their functioning, and economical to fabricate and produce.

Other features and advantages will hereinafter appear.

In the drawings accompanying this specification, similar characters of reference are used to designate like components throughout the several views, in which:

' FIG. 1 is an axial sectional view, enlarged, of an improved shot shell construction as provided by the inven tion. a

FIG. 2 is a rear end elevational View of the improved shot shell construction of FIG. 1.

FIG. 3 is a side elevational view, enlarged, of the novel force-absorbing wad structure provided by the invention.

FIG. 4 is a top plan view of the wad construction shown in FIG. 3.

FIG. 5 is a front elevational view of the improved primer supporting base member as provided by the invention.

FIG. 6 is a rear elevational veiw of the base member shown in FIG. 5.

FIG. 7 is a side elevational view of a shell construction made in accordance with the invention, after firing. This figure shows the line of separation between the nose portion and the body portion of the shell case, such line being slightly jagged. The shell is illustrative of the type of separation obtained approximately 98% of the time when utilizing the novel wall-weakening means provided by the invention.

FIG. 8 is a view similar to that of FIG. 7, showing the type of separation obtained approximately 2% of the time, the separation line being more jagged and irregular.

FIG. 9 is a view similar to that of FIGS. 7 and 8, showing the condition of a shell case after firing, when the wall-weakening means provided by the invention is not employed.

FIG. 10 is a view similar to that of FIG. 9 showing another type of separation and rupture of the shell case, taken from the same lot as the shell of FIG. 9.

FIG. 11 is a side elevational View of another shell taken from the same lot as the shells of FIGS. 9 and 10.

FIG. 12 is a side elevational view of still another shell taken from the same lot as the shells of FIGS. 9, 10 and 1 1.

FIG. 13 is a fragmentary section, enlarged, of the front end or nose portion of the shell case.

Referring first to FIG. 1 there is illustrated the novel plastic shell case with bulbous, weakened integral nose in conjunction with a force-absorbing wad having a deeply grooved annular side wall, these components interacting in an advantageous manner to provide a practical and desirable shot pattern while at the same time minimizing the likelihood of rupture of the side walls of the shell case at points appreciably behind the nose. With the present novel shell case and combination as illustrated, the rupture of the case occurs mostly at the base of the rounded nose despite the integral character of said nose and the side walls and despite the smooth wall surfaces of the nose.

In the illustrated embodiment of FIG. 1, the novel case of the shell is indicated generally by the numeral 16), such case being fabricated of suitable plastic substance such as linear polyethylene and by a molding procedure which leaves its back end open for insertion of the various interior components while the front end is closed by a rounded, integral thin-walled nose section 12 shown as having smooth inner and outer surfaces, such nose section being illustrated also as of generally spherical configuration. With the present shell case 10, in addition to the thin-walled smooth bulbous integral front section 112 and annular external shoulder or indention 14 defining and separating the nose section from the side wall of the case, there is further provided an interior annular indention 16 adjacent the shoulder 14 and located slightly forward thereof. The provision of the two, external and internal indentions 14 and 16 minimizes the likelihood of rupture of the cylindrical side wall of the case 10, and is instrumental in confining the rupture of the case to the base of the front integral rounded nose 112 of thinner wall section, as seen in FIG. 7 which will be later explained in further detail. The wall thickness at the indention is small, being preferably on the order of .008 inch to .010 inch although such dimensions are not to be considered as limiting.

The indentions 14 and 16 are formed in the shell case 10 at the time that the same is molded, and as understood at the present time the effectiveness of such indentions in confining the rupture and separation of the shell parts to a circular line which is fairly well defined and is jagged to a minimum extent is in part due to the thinness of the wall section and in part due to the molecular orientation of the plastic substance whereby at the indentions the grain structure has a different direction as compared with the general directions found in the side walls of the shell case and in the rounded nose portion thereof. The indentions or shoulder formations cause the said different directions of the molecular or grain structure and thus constitute an important factor in effecting the circular line of rupture of FIG. 7, as distinguished from the shell ruptures shown in FIGS. 9, 10, 11 and 12. In a lot of 55 shells fired, where interior and exterior indentions such as those shown at 14 and 16 in FIG. 1 were provided, 54 of the shells had relatively clean or smooth severance lines as indicated in FIG. 7 whereas but a single shell had a more jagged and uneven line of separation, as shown in FIG. 8. In a similar quantity of shells wherein there was not provided the internal indention 16 while other factors were the same, the results were as shown in FIGS. 912 wherein the four types of rupture illustrated, including longitudinal side cracks 19, were representative of the entire group.

At its back end the case 10 of the shell is provided with an external flange or shoulder 18, for engagement with the edge of the gun barrel or shell chamber.

Also in accordance with the invention a novel combination is provided comprising the above molded plastic shell case It in conjunction with a highly and controllably compressible, hollow box-like wad structure 20 constituted of resilient plastic substance, said wad structure having bleeder means and circularly extending annular groove formations in the walls thereof, thereby to enable a controlled axial compression of the structure to be effected together with a maximum extent of such compression, and resultant radial expansion by which leakage and blow-by at the wad is prevented. It has been found that a wad structure as thus characterized is also extremely effective in minimizing undesired fracture of the side walls of the shell case 10 and instead confining the fracture mostly to the rounded, smooth-walled nose portion while at the same time producing in conjunction with such localized fracture a desired and practical shot pattern. In

this connection it is considered of importance that the external and internal indentions 14 and 16 of the case 10 effect a uniform, annular fracture zone as above explained. Also, the ribbed or grooved formation of the annular side wall of the wad 20 is considered to function to some extent as a piston having discrete or separate piston rings slidahle in a cylinder, thereby aiding in providing a seal. The groove formation simulating the discrete annular rings may be readily recognized from an inspection of FIGS. 1 and 3, for instance.

Preferably, as in the illustrated embodiment of the invention, the annular side wall of the compressible forceabsorbing wad 20 'has a plurality of deep grooves of differing depths, the said grooves being funther arranged in sets or pairs on opposite sides of a smooth-walled radially expansi'ble intermediate portion 22 of the wad. Thus a pair of grooves 24, 26 is disposed at one side of the smooth-walled intermediate portion 22, whereas a second pair of grooves 28, 30 is disposed at the other or opposite side of the intermediate portion. The grooves 26, 28 are preferably appreciably deeper than the grooves 24, 30, thereby to dispose the bends or fold-s 32, 34 respectively of the grooves 26, 28 inward with respeot to the folds 36, 38 of the grooves 24, 30. By this construction there is avoided any space-consuming pile-up of the inner folds or bonds of the grooves at the time that the wad suffers axial compression in response to ignition of the powder charge. Thus, the wad may be compressed axially to a greater extent than if such pile-up were present. Also, the smooth center portion 22, when the explosion of the shell occurs, expands radially to minimize leakage past the wlad, thereby maintaining a high efiiciency in the use of the powder charge, as at present understood.

Preferably the smooth, intermediate portion 22 of the wad 20 is of slightly smaller diameter than the grooved front and back end portions whereby data imprinted or otherwise applied to said intermediate portion will not be disturbed when the wad is positioned the shell case 10. Instead, as seen in FIG. 1, the intermediate portion 22 will be slightly spaced from the interior walls of the case 10, preventing any tendency for the case to rub off or otherwise disturb the imprint applied to the wad.

The wad 20 is preferably fabricated by a pressure molding or forming operation, being made in suitable gooved molds as is readily understood in the plastic fabricating art. As seen in FIGS. 1 and 3, the wad 20 has integral circular or disk-like end walls 42 and 44, one or both of which may have a central opening 46 which is found necessary in the fabrication procedure. The opening means 46 has a dual and important function. Not only is it essential to the fabrication of the wads, but it enables a bleeding of the from the wad interiors during firing, thereby to effect a control of the axial compression and control of the pressure build-up in the shell case. The wad structure 20 is thinwalled, and formed of a resilient and flexible plastic formulation, as for example polyethylene or plastic substance,

Referring to *FIG. 1, the shell is shown as having a multi-shot projectile means 50 its nose 12 and foremost side wall portions. Disposed behind and preferably in contact with the shot 50 is the novel bellowstype wad structure 20, the outer peripheral surfaces thereof being preferably intimately engaged with the smooth wall surfaces of the case Engaging and to the rear of the wad structure is a disc-like gm wad 54 which may be of the usual cardboard or thick-paper construction. To the rear of the gun wad 54 the powder charge 56.

By the present invention there is also provided a novel and improved supporting base member designated generally by the reference numeral 6%, which constitutes a closure for the back end of the case 10 and which also mounts the primer 62 by which the powder charge 56 is ignited. The supporting base member 60 is fabricated of plastic substance such as a polyethylene or formulation, and is constituted in a novel manner to more securely frictionally retain in place the primer 62.

As seen in FIG. 1, the primer 62 has a striking surface 64 and a metal supporting shell 66 of appreciable axial length, said shell being provided with an outturned flange 68 at its back or outer end.

The primer base 60 is seen was comprising a cup-like and plug-like structure having a central hollow boss 70 provided with a bore to receive the primer shell 66, and further having a peripheral skint 72 surrounding and spaced from the central boss 70. The peripheral skirt 72 is seen to be tapenng in cross section, with a thick base portion 74 and the walls 76, the latter being disposed at the front end of the primer base.

By the present invention the frictional retention of the primer shell 66 within the boss 70 of the primer base 69 is made more effective by the provision of reinforcing ribs or W bs 80, FIGS. 1 land 4, such webs being tapered and extending from the front end portion of the boss '70 in augularly rearward directions to the thick base portion 74 of the skirt 72. As seen in FIG. 4, a total of four such ribs is provided in the illustrated embodiment of the invention. However, a greater or fewer number of ribs may be utilized, as will be readily understood.

The tapered section of the skirt 72, providing the thin forward edge 76, aids in preventing blow-by of gases when the powder charge 5 6 is ignited. The hollow construction of the primer base 60 provides additional space which may be occupied by the powder charge -56, and conjunction with such construction the thin-walled hollow boss 7 0 and the reinforcing webs 80 provide an adequate support for the primer 62 and help to hold the same in place while the aforementioned advantages of the primer base are realized.

The thin walled boss acts to frictionally hold the pnhner 62 in another manner. When the explosion occurs, the internal pressure in the shell case tends to push radially inward the walls of the boss, thereby to cause these to more tightly seize the primer and prevent its dislodgement.

As shown in FIG. 1, the invention also provides an interlocking construction between the primer base 66 and the shell case 10. Such interlocking construction com prises an annular lip 32 extending rearward from the external flange 18 of the shell case, the said lip having an inturned edge 84 which is formed over the back of the peripheral portion of the primer base 60. Preferably the said peripheral portion has an annular recess 86 to accommodate the inwardly formed edge 84. The opera tion of forming the edge 84 is done after assembly of the primer base 60 to the shell case. By this construction there is effected a positive, secure retention of the primer base 66) in the shell case.

In operation, the shell functions in the following mannor, as at present understood. Referring to FIG. 1, upon the primer 62 being struck by the firing pin or equivalent device of the gun, it will ignite the powder charge 56, which will then immediately propel in a forward direction the gun wad 54. Such wad will initially meet with very little resistance from the force-absorbing wad 2%, by virtue of the thin, ribbedwalls and the resilient plastic construction of such wad. A cushion effect is also had because of the air contained in the vented box-like wad 20, but even with such cushion effect the axial compres sion of the wad 20 occurs at a very rapid but controlled rate since the annular side wall thereof is already wrinkled or ribbed by virtue of the annular groove formation with which the wad is fabricated and since one or both of the end walls are vented. The thin wad walls and the dilfering depths of the grooves 24, 26, 28 and 30 enable a maximum degree of compression of the wad to be experienced. The smooth cylindrical center portion 22 of the Wad 29 will expand radially and will be maintained in intimate engagement with the inside walls of the shell case 20. The gun wad 54 will be impelled forwardly under a mounting restraining force until it virtually completely axially compresses and collapses the force-absorbing wad 20. Meanwhile the charge of shot St) is being subjected to an increasingly greater force. Such greater force, in being transmitted to the rounded nose 12 of the case 10, will sever the said nose from the remainder of the case along the weakened zone formed by the indentions 14, 16 whereupon the shot 50 and wads 54, 20 will be propelled from the gun barrel. The provision of the indentions 14-, 16 in the exterior and interior of the case 10 has the effect of preventing uncontrolled rupture of the side wall, and instead confines such rupture to the base of the rounded nose portion 12.

It will now be understood that by the present invention there has been provided a-novel and improved, controllably and highly axially compressible force-absorbing wad in the structure 20, which effectively reduces the magni tude of the peak pressures resulting from ignition of the powder. In conjunction with such action the provision of the external and internal indentions 14, 16 at the base of the smooth-surfaced integral nose section 12 all contribute to localize the rupture of the shell case at the base of the nose portion and to provide a satisfactory and desirable shot pattern. Upon axial compression of the force-absorbing wad 2% there is a tendency for the outer peripheral portions of the wad to be forced radially outward into intimate contact with the smooth interior wall of the case 10, and thereafter with the interior wall of the gun barrel, such portions having a sealing effect somewhat in the nature of piston rings carried by a piston Within a cylinder. After the wad 20 leaves the gun barrel it rapidly loses velocity because of its very small mass and comparatively large area, whereby it does not 7 travel any appreciable distance to adversely effect the shot pattern.

By the invention, the provision of the smooth-walled intermediate portion 22 of the force-absorbing wad 20 provides a surface on which data, indicia and the like may be imprinted. Thus, when the wad is utilized in conjunction with a shell case having walls which are transparent or translucent, the said indicia may be readily read through the transparent or translucent walls, for the information of the user.

Variations and modifications may be made within the scope of the claims, and portions of the improvements may be used without others.

What is claimed is:

1. A gun shell comprising, in combination:

(a) a shell case,

(b) a multi-shot projectile means in the nose of the shell case,

() a box-like force-absorbing wad in the case, disposed behind the projectile means, said wad comprising:

(1) a round, hollow, flexible and resilient tubular one-piece preformed plastic structure having closed ends including spaced-apart substantially parallel end Walls and having an annular solid and imperforate side wall extending between and joining the end walls,

(2) said annular side wall having a preformed grooved formation comprising at least one deep, circularly-extending annular permanently formed groove characterized by a relatively wide mouth portion with respect to the length of the tubular structure,

(3) all corresponding, circumferentially spaced portions of the groove being equi-spaced from an end wall, and

(d) a powder charge disposed behind the force-absorbing wad,

(e) the preformed grooved formation in the annular side wall facilitating ready, uniform axial collapse of the wad upon ignition of the powder charge so as instantly to smooth the explosive force.

2. A gun shell as in claim 1, wherein:

(a) the preformed grooved formation of the wad comprises a plurality of spaced-apart deep, circularly extending annular, permanently formed grooves all characterized by relatively wide mouth portions with respect to the length of the tubular structure, and

(b) all corresponding circumferentially spaced portions of said grooves being equi-spaced from an end wall.

3. A wad as in claim 2, in which the grooves are of different depths to enable a maximum extent of contraction to be had.

4. A force-absorbing gun-shell wad as in claim 2, in which the side Wall has an intermediate smooth cylindrical portion and has at least one of the said grooves on each side of said intermediate portion.

5. A gun shell wad as in claim 4, in which there are pairs of the said grooves disposed on opposite sides of the intermediate portion, the grooves of each pair having differing depths.

6. A gun shell Wad as in claim 4, in which the intermediate cylindrical portion has a diameter slightly smaller than the maximum diameter of the remainder of the annular side walls, said intermediate portion being expansible to the said maximum, diameter upon the wad experiencing axial contraction.

References Cited in the file of this patent UNITED STATES PATENTS 1,908,314 Brownsdon May 9, 1933 2,073,609 Court Mar. 16, 1937 2,476,291 Garber July 19, 1949 2,665,635 Morel Jan. 12, 1954 2,823,611 Thayer Feb. 18, 1959 2,894,456 Olin July 14, 1959 2,936,709 Seavey May 17, 1960 2,953,990 Miller Sept. 27, 1960 FOREIGN PATENTS 9,975 Great Britain of 1885 226,198 Great Britain May 21, 1925 1,146,646 France May 27, 1957 

1. A GUN SHELL COMPRISING, IN COMBINATION: (A) A SHELL CASE, (B) A MULTI-SHOT PROJECTILE MEANS IN THE NOSE OF THE SHELL CASE, (C) A BOX-LIKE FORCE-ABSORBING WAD IN THE CASE, DISPOSED BEHIND THE PROJECTILE MEANS, SAID WAD COMPRISING: (1) A ROUND, HOLLOW, FLEXIBLE AND RESILIENT TUBULAR ONE-PIECE PREFORMED PLASTIC STRUCTURE HAVING CLOSED ENDS INCLUDING SPACED-APART SUBSTANTIALLY PARALLEL END WALLS AND HAVING AN ANNULAR SOLID AND IMPERFORATE SIDE WALL EXTENDING BETWEEN AND JOINING THE END WALLS, (2) SAID ANNULAR SIDE WALL HAVING A PREFORMED GROOVED FORMATION COMPRISING AT LEAST ONE DEEP, CIRCULARLY-EXTENDING ANNULAR PERMANENTLY FORMED GROOVED CHARACTERIZED BY A RELATIVELY WIDE MOUTH PORTION WITH RESPECT TO THE LENGTH OF THE TUBULAR STRUCTURE, (3) ALL CORRESPONDING, CIRCUMFERENTIALLY SPACED PORTIONS OF THE GROOVE BEING EQUI-SPACED FROM AN END WALL, AND (D)A POWDER CHARGE DISPOSED BEHIND THE FORCE-ABSORBING WAD, (E) THE PREFORMED GROOVED FORMATION IN THE ANNULAR SIDE WALL FACILITATING READY, UNIFORM AXIAL COLLAPSE OF THE WAD UPON IGNITION OF THE POWDER CHARGE SO AS INSTANTLY TO SMOOTH THE EXPLOSIVE FORCE. 